S D Med. 2026 May;79(suppl 5):s37.
ABSTRACT
BACKGROUND: Chronic pain affects nearly one quarter of U.S. adults and remains difficult to treat with existing pharmacologic therapies. High-definition transcranial direct current stimulation (HD-tDCS) has emerged as a potential non-invasive neuromodulation approach. The insular cortex plays a central role in pain perception and represents a promising stimulation target. Capsaicin-induced hyperalgesia provides a validated experimental pain model for studying analgesic interventions.
OBJECTIVE: To determine whether HD-tDCS targeting the insular cortex modulates thermal sensitivity and subjective pain perception in a capsaicin-induced pain model.
METHODS: Fifteen healthy participants underwent both active and sham HD-tDCS conditions. Capsaicin was applied to induce localized thermal hyperalgesia. Thermal sensory testing was performed before and after stimulation, including heat pain threshold (HPT), thermal sensory limen (TSL), and numeric rating scale (NRS) pain ratings. Repeated-measures ANOVA evaluated the effects of time and stimulation condition.
RESULTS: Capsaicin application increased thermal sensitivity and pain ratings across participants. However, no significant stimulation × time interaction was observed for HPT, TSL, or NRS scores, indicating no detectable difference between active and sham HD-tDCS conditions.
CONCLUSIONS: In this pilot study, insular HD-tDCS did not significantly alter thermal sensitivity or pain perception in a capsaicin-induced pain model. These findings may reflect limited statistical power given the small sample size. Larger studies are needed to determine whether targeted neuromodulation of the insula can modulate acute pain processing.
PMID:42526006
